This invention relates to a gas solenoid valve of the type which is designed by to constantly control the feeding amount of a fuel gas means of an electric signal emitted from outside when a fuel gas is fed into gas appliances such as hot-water heaters.
Heretofore, there is known a gas valve of this type wherein a hollow cylindrical coil-holder is inserted in ring shaped magnets and an iron core is accomodated within said cylindrical hollow of the coil-holder. In this prior art, although the magnets which are actuated with a magnet coil wound around the coil-holder for regulating the position of the coil-holder are molded and covered at their outer peripheries with a synthetic resin, the synthetic resin often leaks through a gap and is hardened to form a fin. When the fin grows, the outer surface of the coil-holder is caught by its tip end, thereby disturbing the smooth movement of the coil-holder.
Also, there is known another gas valve wherein the position of a plunger for actuating a valve disc is controlled by means of adequately controlling the amount of current flowing into a magnetic coil, so that the amount of gas to be fed into a governor can be controlled. In order to continuously and accurately regulate the position of the plunger by means of an electric signal emitted from outside as in the foregoing case, it is essential to minimize the mechanical resistance, as much as possible, caused by the sliding movement of the plunger which contacts with other portions while sliding.
To this end, the afore-mentioned prior art adopts a means for supporting both the upper and lower ends of the plunger by a leaf spring. However, in such supporting structure, since the force received from the supporting spring varies depending on the position of the plunger, it is difficult to accurately set the corresponding relationship between the value of the controlling current applied from outside and the position of the plunger.
The present invention is provided in order to eliminate the above-mentioned disadvantages which were inherent in the conventional gas valves.